Neurosurgery has become safe with less morbidity, mortality from its origin to till date with evolution of technology like Operating Microscope, Neuro navigation and Anesthesiology techniques. Functional Neurosurgery is the present concept wherein the preservation of the functional aspect of the structures unaffected by the disease during the surgery for the maximum benefi ts in terms of quality of life is under evolution. Intra operative Neuro physiological Monitoring (IONM) has become vital peroperatively in aiding the surgeon to make decisions in method of
surgery, dissection, instrumentation methodologies during spine surgery, maximize the excision in case of tumor surgeries with preservation of the vital neuronal structures.
Intra operative neuro monitoring is the use of electro physiological methods such as electroencephalography (EEG),
electromyography (EMG), and evoked potentials (SSEP, MEP, Bipolar stimulation etc.,) to monitor the functional integrity of certain neural structures (e.g., nerves, spinal cord and parts of the brain) during surgery. Apart from Neurosurgeons orthopedic, otolaryngologist and urology surgeons have all utilized neuro monitoring as well.
To accomplish these objectives, for patients undergoing operations involving the nervous system or which pose risk to its anatomic or physiologic integrity a member of the surgical team with special training in neurophysiology obtains and co-interprets triggered and spontaneous electro physiologic signals from the patient periodically
or continuously throughout the course of the operation with special an anesthetic technique for aiding
the monitoring without interference to the patients stability and appreciation.
EMG is used for cranial nerve monitoring in skull base cases and for nerve root monitoring and testing in spinal surgery. ABR (a.k.a. BSEP, BSER, BAEP) is used for monitoring of the acoustic nerve during acoustic neuroma and brain stem tumor resections.
Our Hospital Experience
Being the only Centre to have the Intra operative Neuro physiological Monitoring Medtronic device in Neurosurgery at Coimbatore we have performed more than 20 surgeries so far for complex surgeries like Acoustic Neurofi broma for functional facial nerve preservation, spinal Cord Tumors at Cervical, dorsal level, L1, S1, Dumb bell tumors, Meningomyeloceles, skull base tumors where monitoring of the lower cranial nerves and Brain stem integrity, became essential using MEP, EMG, bipolar stimulation for functional preservation of the tracts, roots successfully and were able to functionally preserve the patients neurology along with near total resection of the lesions.
MEP was used primarily in spinal surgeries with instrumentation requirements for evaluating the safety of roots, tracts during instrumentation and correction of deformities.
Needless to say how should be a patient when you preserve the facial function, prevent limb weakness along with total excision of the lesion or correct deformity with this aid.
There is a learning curve for the surgeon, Anesthetist and the Neuro physiologists involved during surgery initially with little increase in the duration of surgery and change in anesthesia, surgical protocols but over cases it is corrected and haven’t changed the duration or safety overall but indeed increase the confi dence for the surgeon during surgical procedures.
Though it increases the cost of surgery marginally functional preservation aids in less post operative stay, less or no physiotherapy, decreases the mental agony, faster return to work for the patients. Large Rt L1 dumb bell schwanomma and midline anteriorly placed infl ammatory pathology required Excision by corpectomy aided by IONM with no defi cits post operatively